Boilers which are used in institutional constructions such as hospitals, nursing homes, greenhouses and the like, which lack adequate backup heating protection require constant maintenance. Many boilers, lacking maintenance are damaged and/or destroyed from low water, fuel cut-off control failures. These failures, if not anticipated, not only endanger the life of the boiler, but also result in developing serious conditions which may be destructive of the boiler and/or result in conflagrations to institutional constructions which are served by the boiler. It has been ascertained that 90 percent of boiler accidents occur as a direct result of low-water, fuel cutt-off control failures, due to poor control maintenance or none at all. Contributing to the problem is the fact that most building owners resist opening the boilers up for control maintenance work, due to the resultant of loss of system sealing as in hot water heating boilers, this problem being aggravated by the prospect that stop valves in a given system may be defective to the extent that they do not resist and hold vapor pressures which have built up in a given boiler.
Low water, fuel cut-off control failures are attributable to varying conditions such as:
A. a given control filling with scale and sludge to the point that the control float becomes defective, will not drop and shut off the burner as and when the boiler has exhausted its supply of water;
B. as a control float may become water logged or disconnect from its stem, a handyman engineer may either lock the linkage thereof in place or jump the electrical switch to keep the boiler going rather than drain the boiler of its water, sufficiently to repair the faulty control;
C. worn linkages between the control float stem and electric switch may render the control useless.
In the prior art repairing the control requires draining which often involves loss of system seal, requiring in large systems as much as several days to reestablish seal with the attendant loss in heating effect for a given institutional building and economic failure.
According to this combination invention, one may now isolate the vertical leg of a boiler's water column containing the low water, fuel cut-off control and either repair or replace the control or the complete vertical leg of the boiler water column without draining the boiler and/or risking loss of system seal. With respect to the art, currently extant, the invention is directed to providing a novel system which may be set within a full opening gate valve of a boiler to provide both positive hookup and seal from atmosphere; to provide a universal main valve body capable of use with either reamer or choke. The boiler, reamer and/or choke herein is designed to prevent loss of water during the setting of the choke into the piping or the removal thereof. The body of the present system is adapted for retraction of the choke and/or reamer and to sustain it while preparing for installation or disconnection. Vents provided herein vent off undesired air from the water column. Suitable packing is provided to permit variation of depth of choke while maintaining a given water seal. For the first time a reamer head is provided on the choke assembly, permitting the removal of scale and the like for an optimum uniform seat for the choke.
Within this invention means are provided to insure against loss of water from a pressurized or full system while at the same time preventing air from entering the piping or boiler vessel from the atmosphere. The key safety feature of the invention is to prevent scalding of personnel by means of the use of a packing gland and secondly, the compression rod is provided with a safety plate, capable of slipping back over the wrench element, thereby reducing the possibility of the compression rod assembly being thrust backwards by boiler pressure into the user.
The art is distinguished as follows. In Maish U.S. Pat. No. 2,937,666 the concept involves an internal tube seal which differs in that its purpose is for sealing a tube end, which is capable of introducing a fluid through it for testing purposes. It does not provide means for sealing its operation at all times from the atmosphere, nor is it capable of permitting a choke to be set in place and then removing its housing, thus leaving the choke in place in the piping as and when it may be necessary to remove piping behind it. Moreover, the device of Maish is not provided with a reamer head to allow a more uniform sealing surface on the internal surface of the piping; nor does the stem or compression rod assembly permit its adjustment as to depth to avoid such apparatus within the system as fittings. That concept moreover, would not prevent loss of water and admittance of ar during the operation of setting the choke in place and removing it and the O-ring in that concept would not provide a positive seal inside a pipe having an irregular surface caused from deposits of scale and varying degrees of pitting.
In the MacAllister U.S. Pat. No. 2,214,171, a cleanout tool is defined which differs in that its purpose is restricted to cleaning out, whereas major body components of the present invention serve more than one purpose. Again, through the utilization of MacAllister water will be lost and air allowed to enter the piping when the device is being installed or removed from the piping and sealing the fluid inside, a tapered plug is forced against the head of an open fitting, causing the loss of fluid until the device was sealed.
In the Christman U.S. Pat. No. 775,124, the concept thereof is not equipped with a body or housing to provide a seal when connecting the device or placing the choke in position. Moreover, as before, no means are provided for preventing loss of fluid or admittance of air into piping when the choke is being inserted or removed and no means are provided for purging air from a water column after repairs may have been completed. No safety device is established in this concept, excepting that of a deflector mounted on the handle of the apparatus.
In the Bay U.S. Pat. No. 2,313,042, the concept is directed to a condenser tube reamer such as may be useful in cleaning water cooled tubes of steam surface condensers. It does not provide means of reaming a pipe or tube in a pressurized fluid system without the loss of that fluid whereas in the present invention a seal is provided by means of the packing gland in the valve body to keep the apparatus sealed from the atmosphere at all times.